RESUMEN
BACKGROUND: Intrauterine exposure to maternal vitamin D status <50 nmol/L of serum 25-hydroxyvitamin D [25(OH)D] may adversely affect infant body composition. Whether postnatal interventions can reprogram for a leaner body phenotype is unknown. OBJECTIVES: The primary objective was to test whether 1000 IU/d of supplemental vitamin D (compared with 400 IU/d) improves lean mass in infants born with serum 25(OH)D <50 nmol/L. METHODS: Healthy, term, breastfed infants (Montréal, Canada, March 2016-2019) were assessed for serum 25(OH)D (immunoassay) 24-36 h postpartum. Infants with serum 25(OH)D <50nmol/L at 24-36 h were eligible for the trial and randomly assigned at baseline (1 mo postpartum) to 400 (29 males, 20 females) or 1000 IU/d (29 males, 20 females) of vitamin D until 12 mo. Infants (23 males, 18 females) with 25(OH)D ≥50 nmol/L (sufficient) formed a nonrandomized reference group provided 400 IU/d. Anthropometry, body composition (DXA), and serum 25(OH)D concentrations were measured at 1, 3, 6, and 12 mo. RESULTS: At baseline, mean ± SD serum 25(OH)D concentrations in infants allocated to the 400 and 1000 IU/d vitamin D groups were 45.8 ± 14.1 and 47.6 ± 13.4, respectively; for the reference group it was 69.2 ± 16.4 nmol/L. Serum 25(OH)D concentration increased on average to ≥50 nmol/L in the trial groups at 3-12 mo. Lean mass varied differently between groups over time; at 12 mo it was higher in the 1000 IU/d vitamin D group than in the 400 IU/d group (mean ± SD: 7013 ± 904.6 compared with 6690.4 ± 1121.7 g, P = 0.0428), but not the reference group (mean ± SD: 6715.1 ± 784.6 g, P = 0.19). Whole-body fat mass was not different between the groups over time. CONCLUSIONS: Vitamin D supplementation (400 or 1000 IU/d) during infancy readily corrects vitamin D status, whereas 1000 IU/d modestly increases lean mass by 12 mo. The long-term implications require further research. This trial was registered at clinicaltrials.gov as NCT02563015.
RESUMEN
BACKGROUND: Vitamin D status at birth is reliant on maternal-fetal transfer of vitamin D during gestation. OBJECTIVES: We aimed to examine the vitamin D status of newborn infants in a diverse population and to subsequently identify the modifiable correlates of vitamin D status. METHODS: In this cross-sectional study, healthy mother-infant dyads (n = 1035) were recruited within 36 h after term delivery (March 2016-March 2019). Demographic and lifestyle factors were surveyed. Newborn serum 25-hydroxyvitamin D [25(OH)D] was measured (standardized chemiluminescence immunoassay) and categorized as deficient [serum 25(OH)D <30 nmol/L] or adequate (≥40 nmol/L). Serum 25(OH)D was compared among categories of maternal characteristics using ANOVA; each characteristic was tested in a separate model. Subgroups (use of multivitamins preconception and continued in pregnancy compared with during pregnancy only) were matched (n = 352/group) for maternal factors (ancestry, age, income, education, parity, and prepregnancy BMI) using propensity scores; logistic regression models were generated for odds of deficiency or adequacy. RESULTS: Infants' mean serum 25(OH)D was 45.9 nmol/L (95% CI: 44.7, 47.0 nmol/L) (n = 1035), with 20.8% (95% CI: 18.3%, 23.2%) deficient and 60.7% (95% CI: 55.2%, 66.2%) adequate. Deficiency prevalence ranged from 14.6% of white infants to 41.7% of black infants. Serum 25(OH)D was higher (P < 0.0001) in infants of mothers with higher income, BMI < 25 kg/m2, exercise and sun exposure in pregnancy, and use of multivitamins preconception. In the matched-subgroup analysis, multivitamin supplementation preconception plus during pregnancy relative to only during pregnancy was associated with lower odds for vitamin D deficiency (ORadj: 0.55; 95% CI: 0.36, 0.86) and higher odds for adequate vitamin D status (ORadj: 1.47; 95% CI: 1.04, 2.07). CONCLUSIONS: In this study most newborn infants had adequate vitamin D status, yet one-fifth were vitamin D deficient with disparities between population groups. Guidelines for a healthy pregnancy recommend maternal use of multivitamins preconception and continuing in pregnancy. An emphasis on preconception use may help to achieve adequate neonatal vitamin D status.This trial was registered at clinicaltrials.gov as NCT02563015.
